Introduction
Venetian blinds date back to Marco Polo and Venice. Many suspect Marco Polo "discovered" the Venetian blind in Persia where it was known as a Persiana blind and caused the blind to become popular by introducing it to more populated and commercialized areas.
Evidence exists that the technical construction of the Venetian blind has not substantially changed in over 200 years. The earliest surviving mechanical drawing of a Venetian blind is believed to be by Roubo in L'Art du Menuisier, Paris, 1769. It shows a suspended and tiltable multiple slat blind that raises and lowers.
John Webster advertised in the Philadelphia Journal on Aug. 20, 1767, " . . . the newest invented Venetian sun blinds for windows, on the best principles, stained to any color, moves to any position, so as to give different lights, screens from the scorching rays of the sun, draws a cool air in hot weather, draws up as a curtain, and prevents from being overlooked, and is the greatest preserver of furniture of anything of the kind ever invented."
An engraving by Robert Edge Pine and Edward Savage of Congress Voting Independence shows Venetian blinds in Independence hall in Philadelphia in 1776.
Since its beginnings numerous Venetian blind developments have not significantly changed this classic product other than on a refined scale such as narrow ladder cords replacing wide ladder tapes, conversion to contemporary materials such as aluminum and plastics, and component improvements such as high-ratio gear wands replacing direct-drive tilt cords.
There appears to be at least two causes for the lack of quantum-leap improvements. One is that Venetian blinds have been the subject of consistent refinement over such a long time by so many contributors they were believed to have evolved to their most efficient generic form. In such an environment it is extremely difficult to bring about a revolutionary improvement to a product that has experienced such evolutionary refinement.
The second cause is that in solving one problem the so called improvements either have inadvertently created another one or have compromised a prior accepted benefit to a level below consumer acceptance.
Illustrative of this dilemma are the blinds of U.S. Pat. Nos. 1,590,886 to Carella and 3,074,127 to Ellis. In each instance efforts were made to have the slats hide the vertical members of the blinds but to do so they required the tilting means to be secured to the bottom casings of the windows. As a consequence the raising and lowering of the slats was prevented, the installments were complicated, and among other things, costs increased, and the blinds would generally require a relatively high degree of window squareness for the product to fit properly.
The point is that continuing efforts to improve Venetian blinds over hundreds of years commonly have not produced acceptable results.